Answer:
The trial balance is just that, a "trial" balance. It shows where the company stands at a certain point in time. the "adjusted trial balance" does the same thing with one slight difference, it's the balance after all adjusting entries are made. These entries may include, the expiration of pre-paid insurance, payments received and the closing of the books for the period.
For example, you can begin your month with a trial balance, to ensure everything is correct, at the end of the month you have made all your adjusting entries and transactions, after this point you want to have your adjusted trial balance (because entries have been "adjusted" for the period)